The invention relates to the regulation of a switching transistor and more particularly to preventing the switching transistor from going into saturation while in the on or conductive state.
The most popular method of regulating conduction of switching transistors is the clamp diode method. This method utilizes a diode between the base and collector elements of the switching transistor. This method has found success even though an excess amount of base drive power is wasted by shunting excess base drive power through the transistor.
Another circuit for regulating base drive is disclosed in NASA report No. NASA TN 0-6511 dated December, 1971. This method is similar to the instant invention except a plurality of series diodes are employed between the emitter of the drive regulator and the base of the output transistor. This scheme provides a minimum of 2.1 volts on the collector of the output transistor which is three times greater than that level required for 0 collector to base voltage. This results in three times the conduction dissipation of the output transistor and is therefore undesirable in terms of circuit efficiency.
Other methods of regulating base drive power employ complicated feed back control circuits requiring a substantial number of additional electrical components for their operation. This increases economic cost, weight and susceptibility to failure.
There would be immediate acceptance by industry of a means for regulating base drive to a switching transistor that was more efficient, comprised of a limited number of components and could be produced at a reduced economic cost over the prior art devices.